The present invention generally relates to a press tool for non-detachably connecting through cold deformation a fitting and an end portion of a metal pipe received in a socket of the fitting, and more specifically to a press tool of a type having a wraparound ring which includes a plurality of hinged links for placement over the socket of the fitting, whereby the wraparound ring is open at one closing area between two neighboring links and forms grip points at the closing area for application of a closing device.
Various designs have been developed for press tools to press together a fitting and a pipe end. Reference is made for example to German Pat. No. DE 42 40 427, published Jan. 20, 1994.
A press tool of this type is known for non-detachably connecting pipes of a nominal width over 54 mm with a fitting through cold deformation. The socket of the fitting receives the end of the metal pipe and is formed with a bead that faces inwardly for receiving an O ring. The cold connection is realized by positioning a wraparound ring comprised of hinged links about the bead and the socket adjoining the bead, and applying an electrohydraulically operated closing device to bring together the two links bounding the open closing area. This results in a cold deformation of the bead, of the socket zones adjoining the bead and of the associated regions of the metal pipe. The cross-sectional contour of the socket and the metal pipe in the deformed area is polygonal with arched sides and rounded corners. In order to realize this deformation, significant pressing forces must be applied so that the press tool is complicated and has great dimensions and thus is difficult to handle. This type of press tool is also expensive and therefore was generally leased by users and purchased only on rare occasions.
In metal pipes up to a diameter of 54 mm, the pressed connection between the socket of the fitting and the metallic pipe end is realized by an electrohydraulic press tool, with the press tool provided with a clamping device having two jaws that bound a pressing zone. These jaws are swingably mounted to adapters which extend transversely to the longitudinal axis of the clamping device. The jaws grab around the socket of the fitting in the area of a bead for receiving the sealing element and on both sides of the bead. A force is applied immediately before, on and behind the bead to realize a non-detachable joint. Through cold formation of the bead, the sealing ring is pressed onto the pipe end while indentations spaced about the circumference are formed before and behind the bead for plastically forming the pipe end in the area of the indentations.